Embedded devices are resource constrained systems (e.g., memory, speed) that are expected to deliver the needs of a specific application. To mitigate the memory limitation, the functionality of the embedded device can be extended by attaching non-volatile memory (e.g., via a universal serial bus (USB)) to the embedded system and recognizing the non-volatile memory by means of firmware. If the memory constraints are solved, different applications can run on the same embedded device by making use of sensors and actuators as shared resources. It has been proposed to use cloud technology as an extensible computation resource (e.g., for executing an intensive non-real time application) and a sensor as a shared resource for monitoring applications.
More specifically, to mitigate the memory limitation, Giuseppe (US Patent Pub. No. 2011/0258618) extended the functionality of the embedded device by attaching non-volatile memory (USB) to the embedded system and recognizing it by means of firmware. If memory constraints are solved, different applications can run on the same embedded device by making use of sensors and actuators as shared resources. Lee (System Architecture Directions for Tangible Cloud Computing” October 2010; MEE CDEE Page(s):258-262) has proposed to use a cloud as an extensible computation resource and sensor as a shared resource for monitoring applications. The idea of executing process intensive non real-time applications in a cloud is given by McLaughlin (U.S. Pat. No. 7,970,830). Usage of cloud services for real-time systems (Hard/Soft) which can include control algorithms to activate an actuator is not described in the above patents or literature.
Additionally, in almost all applications actuators are used and it requires a unique control mechanism unlike the sensor parameters, hence using cloud services for control mechanism can extend the horizon of cloud. Unfortunately, executing the control mechanism as a cloud service is not practical due to the non-deterministic nature of the cloud infrastructure. In addition to that problem, there is a need to download embedded software that requires updates to add features or correct errors. Some updates are costly since they can be programmed only by OEM's or dealers. Derrick (U.S. Patent Pub. No. 20110289493) has proposed to use a portable device that provides embedded software to the embedded system. However, this approach requires the need for maintenance of a device just for software updates. Another common problem encountered in the embedded system is that it cannot be stopped for debugging purposes. Adrain (U.S. Patent Pub. No. 20060150021) has disclosed an analysis device to monitor the behavior of the embedded system in real time. It is disadvantageous to use such a system since the analysis device memory should at least have the same bandwidth as the embedded device. With the advancement in embedded processors in terms of memory capacity and speed, the analysis device has to be replaced often to meet the memory requirement.
As an example, an embedded device can be associated with a gas turbine. A gas turbine of any power or process plant has a number of components such as journal bearings, rotors, shafts, compressors (and blades at various stages), combustors, nozzles, buckets, and casings. The journal bearing supports the moving rotor. The journal bearing has a bearing, journal, a rotor, a shaft, and lubricating oil. The lubricating oil, which is subject to high pressures, has a high viscosity and can withstand high pressure so that that it can take up the large rotor load during a state of rest. Additionally, during the rotation of the rotor, the lubricating oil is squeezed by the rotor and the rotor moves to the right (for a counterclockwise load). Since there is a large temperature increase during such operation, the viscosity of the oil decreases and hence the separation between the journal and the bearing decreases. This decrease in separation causes large scale friction and the bearing degrades. There are also various other failure modes of journal bearings such as oil whirl, oil whip, and rotor unbalance. These failure modes, if not monitored, can be catastrophic and can cause substantial loss to the gas turbine and the plant.